The long-range goal of this project is to provide the clinician with a scientifically-based means of determining optimal treatment(s) for anomia in patients with neurodegenerative disorders, including primary progressive aphasia (PPA) and Alzheimer's disease (AD). The desired outcomes are a longer period of preservation of function (Prophylaxis) for words that can be retrieved successfully, and improvement (Remediation) for words that cannot be retrieved successfully at baseline. Semantically-based treatment will be compared with lexically-based treatment, and maintenance of treatment gains will be measured at one-month, eight months, and 15 months post-treatment. Participants will be persons with all three types of PPA -- semantic (svPPA), nonfluent/agrammatic (nfvPPA), and logopenic (lvPPA) -- and persons with AD who have significant word- finding problems (anomia). Through the use of a within-subjects design, each participant will receive both treatments, with different items in the two treatment sets. Participants who are unable to travel to the laboratory for the required number of treatment and evaluation sessions will participate remotely via videoconferencing. At baseline, structural MRI scans will be obtained, and two semantic batteries will be administered: one consisting of conceptually-based tests (without words), and one consisting of lexically-based tests. The results of these test batteries will be used to compute a Relative Lexical-Semantic/Conceptual-Semantic impairment measure for each participant. Based on theoretical considerations discussed in the proposal, it is predicted that persons whose lexical impairments are greater than their conceptual impairments will show greater treatment effects for lexically- based treatment than for semantically-based treatment, while those with a greater conceptual impairment will show greater treatment effects with a semantically-based treatment than a lexically-based treatment. Further, it is predicted that the Relative Lexical-Semantic/Conceptual-Semantic impairment measure will provide additional information about the treatment effects, above and beyond what can be obtained from the Diagnostic Subgroups and demographic variables. The use of baseline atrophy in predicting treatment effects will also be tested; Specifically, it is predicted that participants with baseline atrophy in the left temporal pole and/or the left inferior temporal gyrus will be more likely to demonstrate generalization to untrained items when semantic treatment is utilized, compared to the lexical treatment condition. The validation of techniques for improving word-finding, and hence communication, in persons with PPA and AD is of great significance for these patients and their families and caregivers. And being able to determine, on the basis of scientific data, which treatment is most likely to succeed for a given patient, is the aspiration of every clinician.